1. Field of the Invention
This invention relates to tailgates for trucks, and more particularly, to a tailgate easily convertible to a loading ramp.
2. Description of the Prior Art
Trucks having flatbeds partially surrounded by sidewalls are commonly used to haul heavy loads. Since the beds of these trucks are spaced a considerable distance above the ground, mechanized devices must often be used to raise heavy loads to the bed. Hydraulic or mechanical lifts placed adjacent the rear of the beds are satisfactory. However, their great expense effectively prohibits their widespread use with the most common variety of such trucks, namely, the pickup truck. Another common device used to facilitate loading of trucks is the loading ramp. Conventional loading ramps are generally carried from place to place by the truck, and their weight and bulk reduce the effective load capacity of the truck. To solve this problem, attempts have been made to utilize the rear doors of trucks as loading ramps. Examples of such devices are disclosed in U.S. Pat. No. 3,861,739, issued to Kinney, U.S. Pat. No. 2,653,845, issued to Benjamin, and Italian Pat. No. 639,021. In these devices, the doors open by pivoting on a vertical axis, and the doors are converted to ramps by pivoting the lower edges of the doors on a horizontal axis. This approach is satisfactory only for doors having a substantial height. It cannot be applied to the wide, relatively low tailgates commonly used on pickup trucks. Specifically, the height of the door must be substantially greater than the distance from the ground to the bed in order to provide a sufficiently gradual incline.
Although the prior art discloses wide and relatively low doors mounted at the rear of vehicles to pivot on either a horizontal or a vertical axis, the doors are not capable of functioning as loading ramps. Examples of such devices are found in U.S. Pat. No. 3,387,406, issued to Coker, et al., and U.S. Pat. No. 3,454,299, issued to Hewitt, et al. In neither of these devices are the doors sufficiently high to extend to the ground even if pivoted downwardly to a vertical plane.
Another approach for combining a tailgate with a loading ramp is disclosed in U.S. Pat. No. 3,756,440, issued to Raap, et al., wherein a separate loading ramp is secured to the tailgate. However, this device does not eliminate the extra weight and bulk of the loading ramp, but merely provides a convenient storage position for the ramp. Furthermore, the loading ramp does not flushly join the tailgate, thereby providing an uneven surface over which heavy objects must pass.
Still another loading ram for a pickup truck is disclosed in U.S. Pat. No. 3,642,156, issued to Stenson. Although Stenson does, in fact, utilize the tailgate as a loading ramp, the tailgate requires telescoping panels and is relatively complex and expensive.